scholarly journals Influence of Grain Boundary Migration on {001} Texture Formation in Al-3 mass%Mg Based Alloys during High Temperature Compression Deformation

2007 ◽  
Vol 48 (8) ◽  
pp. 2002-2007 ◽  
Author(s):  
Kazuto Okayasu ◽  
Hiroki Takekoshi ◽  
Hiroshi Fukutomi
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Texture Formation ◽  
Compression Deformation

Increased Thermal Stability of Co-silicide Using Co-Ta Alloy Films

2001 ◽  
Vol 670 ◽  
Author(s):  
Min-Joo Kim ◽  
Hyo-Jick Choi ◽  
Dae-Hong Ko ◽  
Ja-Hum Ku ◽  
Siyoung Choi ◽  
...  
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Grain Boundary ◽  
Reaction Rate ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Alloy Films ◽  
Post Annealing ◽  
Alloy Process ◽  
Thermal Stability Of

ABSTRACTThe silicidation reactions and thermal stability of Co silicide formed from Co-Ta/Si systems have been investigated. In case of Co-Ta alloy process, the formation of low resistive CoSi2phase is delayed to about 660°C, as compared to conventional Co/Si system. Moreover, the presence of Ta in Co-Ta alloy films reduces the silicidation reaction rate, resulting in the strong preferential orientation in CoSi2 films. Upon high temperature post annealing in the furnace, the sheet resistance of Co-silicide formed from Co/Si systems increases significantly, while that of Co-Ta/Si systems maintains low. This is due to the formation of TaSi2 at the grain boundaries and surface of Co-silicide films, which prevents the grain boundary migration thereby slowing the agglomeration. Therefore, from our research, increased thermal stability of Co-silicide films was successfully obtained from Co-Ta alloy process.

High-temperature high-resolution in-situ microscopy of grain boundary migration and structure change

1990 ◽  
Vol 48 (4) ◽  
pp. 514-515
Author(s):  
Hideki Ichinose ◽  
Tokuji Kizuka ◽  
Yoichi Ishida
Keyword(s):  
High Temperature ◽  
High Resolution ◽  
Grain Boundary ◽  
High Stability ◽  
Boundary Migration ◽  
Structure Change ◽  
Objective Lens ◽  
Video Tape ◽  
Grain Boundary Migration

A high resolution high temperature specimen stage of 200kV HRTEM was newly designed and produced in order to investigate the physical and mechanical nature of materials at high temperature.The atomic process of silicon grain boundary migration and the structure change was successfully observed in-situ at 1000K by the new specimen stage.The high temperature specimen stage consists of a heating specimen holder, a high stability power supply and a high stability current controller. Heat is provided by an induction free double spiral coil heater which is made of tungsten. Excellent current stability, better than 10−6 , prevents the objective lens from the magnetic disturbance which is caused by heating current. The highest temperature of the specimen is designed to be 1100K. The accuracy of the temperature measurement is checked by the melting test of tin. In order to keep the high resolution of the microscope(JEM-200CX) at such high temperature as 1100K an objective lens is also newly designed and produced. Aberration constants of the new lens are respectively Cs=0.7mm and Cc=1.2mm. Resulted resolution at high temperature is as same level as the that of the original JEM-200CX at room temperature. Images are recorded by a video tape recorder.

Effect of Grain Boundary Migration on Texture Formation in Al-3mass%Mg Solid Solution during High Temperature Deformation

2007 ◽  
Vol 558-559 ◽  
pp. 551-556 ◽  
Author(s):  
Kazuto Okayasu ◽  
Hiroki Takekoshi ◽  
Hiroshi Fukutomi
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Grain Boundary ◽  
Boundary Migration ◽  
Fiber Texture ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Grain Boundary Migration ◽  
Strain Rates ◽  
Main Component

Uniaxial compression deformation is conducted on solid solution Al-3mass%Mg and Al-3mass%Mg-0.2mass%Sc with Al3Sc precipitates in the strain rates ranging from 1.0×10-4s-1 to 5.0×10-3s-1 at 723K. High temperature yielding is observed. Fiber texture is constructed in all the deformation conditions. While the main component of the fiber texture changes from {011} to {001} in Al-3mass%Mg alloy with an increase in strain rate, no big change in texture main component is seen for Al-3mass%Mg-0.2mass%Sc alloy with Al3Sc precipitates. It is experimentally shown that the development of {001} fiber texture can be attributed to the grain boundary migration.

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